1. Field of the Invention
The present invention relates to a torque sensor configured to detect a rotational torque transmitted from an input shaft to an output shaft, and a robot apparatus including the same.
2. Description of the Related Art
In recent years, torque sensors have been applied, for example, to an actuator control apparatus employing a force control system and to a driving system such as a haptic device for providing an operator with a sense of force and a tactile sense in addition to visual information and audio information. Here, the force control means a control method for directly receiving a target value of a force to be applied to a work object and realizing the force indicated by the target force. Further, as an output torque is detected and fed back with higher accuracy, more flexible interaction services can be achieved through force orders. Further, the haptic device is a device configured to provide in a realistic manner a user with a sense that the user touches or holds an object in an environment, which is actually not accessible by the user. The haptic device is used in entraining in medical field or other specific techniques, or in a distal procedure in a virtual environment such as a microcosm or an ocean, or a specific or hazard environment such as an atomic reactor. For example, Japanese Patent Application Laid-open No. 2009-95959 discloses a control system of sensing an unknown environment, obtaining an appropriate external force from the ambient environment changing in time, and adjusting a generation force of an actuator so that a target procedure can be achieved.
In general, the torque sensor is provided to a rotational portion supported through a bearing. The torque sensor includes a strain portion to be strained due to a torsion moment, and measures a strain of the strain portion, to thereby detect a rotational torque of the rotational portion.